BOSTON -- The man who confessed to but was never convicted of the "Boston Strangler" murders that terrified this city 50 years ago did commit at least one of the attacks, Massachusetts prosecutors said on Friday, citing new DNA evidence.

A week after the body of Albert DeSalvo was exhumed for further DNA testing, the tests confirmed that he killed 19-year-old Mary Sullivan, in January 1964, the last of 11 victims attributed to the Boston Strangler.

"This leaves no doubt that Albert DeSalvo was responsible for the brutal murder of Mary Sullivan, and most likely that he was responsible for the horrific murders of the other women he confessed to killing," Massachusetts Attorney General Martha Coakley said in a statement.

DeSalvo had confessed to the string of killings of single women around Boston in the early 1960s but later recanted. He was stabbed to death in prison by another inmate in 1973, while serving a sentence for armed robbery and sexual assault.

Authorities last week said the DNA from one of DeSalvo's nephews had a strong link to DNA taken from the scene of Sullivan's murder. Based on that link, authorities exhumed DeSalvo's body and found a match with DNA recovered from the scene where Sullivan was raped and murdered.

Advances in DNA testing allowed officials to confirm the match.

Officials have warned that they do not have similar DNA recovered from the scenes of other victims attributed to the Boston Strangler, which will make it impossible to confirm whether DeSalvo was responsible for all the killings.

Law enforcement experts have long disagreed over the Boston Strangler case, with some contending that all 11 murders may not have been committed by the same person.